6. ADRENAL STEROIDS AND ACTH
363
response to mammalian thyrocalcitonin in the eel (Fig. 11). A possible
explanation for this result is that following removal of the corpuscles of
Stannius there is an elevation of endogenous production of calcitonin
(probably from the ultimobranchial bodies) in response to the hypercalcemia. Under these conditions the target tissues reacting to calcitonin
are already maximally stimulated. Injection of exogenous calcitonin could
produce no further effect (D. K. 0. Chan et aZ., 1968a).
C. Factors Controlling the Corpuscles of Stannius
It is not clear whether there are “tropic” hormones which act upon
the corpuscles of Stannius. Using the goldfish, Chavin (1956) observed
no change in corpuscular histology following hypophysectomy, injection
of ACTH, MSH, whole pituitary extracts, or pituitary transplantation.
Olivereau and Fontaine ( 1965), however, found hypertrophy of the gland
and an enlargement of cell nuclei in the eel, while Hanke et al. (1967)
showed hypertrophy after administration of ACTH to both freshwater
and seawater eels.
Adrenalectomy of the freshwater eel, where there is marked hyponatremia and hypocalcemia, results in regression of nuclear and cell size
of the corpuscles of Stannius; in the seawater eel, where there are elevated
plasma sodium and calcium concentrations following adrenalectomy,
there are pronounced nuclear and cell enlargements (Hanke and Chester
Jones, 1966; Hanke et al., 1967).
Exogenous steroid administration also changes corpuscular histology.
High doses of cortisol and aldosterone were without effect (Hanke and
Chester Jones, 1966) , although the aldosterone antagonist, aldactone, induced hypertrophy of the corpuscles ( Olivereau, 1963b). Deoxycorticosterone pellets lead to a hypertrophy of the cells and an increase in cell
granularity ( Rasquin, 1956).
Infusions of pressor agents such as angiotensin I1 and adrenaline resulted in regression of the corpuscles (Hanke and Chester Jones, 1966);
and injections of vasopressin, probably in pressor amounts, also caused
a loss of granules from the cells of the gland ( Rasquin, 1956).
From these data it is uncertain whether an endocrine axis exists
between the corpuscles of Stannius and other tissues. Certain it is that
the secretions of this gland, unique to teleostomes, require intensive investigation, the most urgent parameter required probably being the
chemical nature of the material( s ) produced.
363
response to mammalian thyrocalcitonin in the eel (Fig. 11). A possible
explanation for this result is that following removal of the corpuscles of
Stannius there is an elevation of endogenous production of calcitonin
(probably from the ultimobranchial bodies) in response to the hypercalcemia. Under these conditions the target tissues reacting to calcitonin
are already maximally stimulated. Injection of exogenous calcitonin could
produce no further effect (D. K. 0. Chan et aZ., 1968a).
C. Factors Controlling the Corpuscles of Stannius
It is not clear whether there are “tropic” hormones which act upon
the corpuscles of Stannius. Using the goldfish, Chavin (1956) observed
no change in corpuscular histology following hypophysectomy, injection
of ACTH, MSH, whole pituitary extracts, or pituitary transplantation.
Olivereau and Fontaine ( 1965), however, found hypertrophy of the gland
and an enlargement of cell nuclei in the eel, while Hanke et al. (1967)
showed hypertrophy after administration of ACTH to both freshwater
and seawater eels.
Adrenalectomy of the freshwater eel, where there is marked hyponatremia and hypocalcemia, results in regression of nuclear and cell size
of the corpuscles of Stannius; in the seawater eel, where there are elevated
plasma sodium and calcium concentrations following adrenalectomy,
there are pronounced nuclear and cell enlargements (Hanke and Chester
Jones, 1966; Hanke et al., 1967).
Exogenous steroid administration also changes corpuscular histology.
High doses of cortisol and aldosterone were without effect (Hanke and
Chester Jones, 1966) , although the aldosterone antagonist, aldactone, induced hypertrophy of the corpuscles ( Olivereau, 1963b). Deoxycorticosterone pellets lead to a hypertrophy of the cells and an increase in cell
granularity ( Rasquin, 1956).
Infusions of pressor agents such as angiotensin I1 and adrenaline resulted in regression of the corpuscles (Hanke and Chester Jones, 1966);
and injections of vasopressin, probably in pressor amounts, also caused
a loss of granules from the cells of the gland ( Rasquin, 1956).
From these data it is uncertain whether an endocrine axis exists
between the corpuscles of Stannius and other tissues. Certain it is that
the secretions of this gland, unique to teleostomes, require intensive investigation, the most urgent parameter required probably being the
chemical nature of the material( s ) produced.